Tail gate operating mechanism



NOV. 5, 1940. BOHNE 2,220,202

TAIL GATE OPERATING MECHANISM Filed Sept. 15, 1959 4 Sheets-Sheet 1 0000015 fioH/Vf INVENTOR.

ATTORNEYS.

Nov. 5, 1940. BQHNE- 2,220,202

TAIL GATE OPERATING MECHANI SM Filed Sept. 15, 1939 4 S eets-Sheet 2 M34 INVENTOR.

ATTORNEYS Nov. 5, 1940. D. .BOHNE TAIL GATE OPERATING MECHANISM Filed Sept. 15, 1939 4 Sheets-Sheet 5 50 QOUGLAS flaw/v5 INVENTOR.

ATTORNEYS.

NOV. 5, 1940. v BQHNE I 2,220,202

TAI L GATE OPERATING MECHANISM Filed Sept. 15, 1939 4 -Sheet 4 004/04/15 flay/v5.

INVENTOR.

ATTORNEYS.

Patented Nov. 5, 1940 ,UNlTED- STATES.

PATESNT OFFICE The present invention relates to new and useful improvements in tail gates for vehicle bodies of the dumping type.

One object of the present invention is to imiprove the construction and mode of operation of the tail gates-of dumping vehiclebodies and so to construct the same that they may be operated in various manners dependent upon condi tions of loads, and character or dump to be made. In the present embodiment of the invention the tail gate is illustrated as of the type which -is adapted to open, either by pivoting the same at its upper edge and permitting its lower edge to swing free of the body of the vehicle, or by pivlo oting the tail gate at its lower edge and permitting its-upper edge to. swing away from the body of the vehicle.

A feature of the invention resides in the provision of power operating means for operating the tail gate, either when it is swung about its upper pivots or its lower pivots to efl'ect the opening of the end of the truck body,

A further feature of the invention resides in the provision of power operated means which may be rendered ineffective under certain operative conditions thereby to permit the tail gate to open under the-influence of the pressure of the load to be dumped and to close by the action of gravity.

A further feature of the invention. resides in a novel arrangement of parts whereby the tail gate may be power operated in any position of the vehicle body when the bodyis of the type which is elevated to eiiect dumping of the contents thereof.

Still a further feature of the invention resides in a. novel means for maintaining the tail gate n body closing position together with means for selectively releasing the holding means to permit of swinging movement of the tail gate about either itsupper or lower pivots as may be desired.

Still a further feature of the invention resides in the novel construction of the power operating -means whereby the same may serve to support the tailgate in a horizontal position when it is swung about its lower pivotal points, thus eliminating the use of supporting chains or other means for retaining the tail gate in the horizontal position.

Still a further feature of the invention resides in the provision of a novel power operating means so constructed and arranged as to operate the ail gate to both its open and closed positions and about its upper" or lower pivotal points.

Other features of the invention relate to certain novel and improved constructions, arrangements andycombinations of parts hereinafter described and particularly pointed out in the claims, the advantages 01' which will be readily understood and appreciated by those skilled in 5 the art. i

The invention will be clearly understood from the. accompanying drawings illustrating the inventlon in its preferred form and the following detailed description of the construction therein 10 shown.

t In the drawings:

Figure 1 is a view in side elevation partly I A broken away illustrating a dump truck equipped with a tail gate operating mechanism constructed 15 in accordance with one embodiment of the present invention. a portion of the operating mechanism being shown in dotted lines in said figure. Figure 2 is a horizontal sectional view on an enlarged scale taken substantially on the line 20 2-2 of Figure 1, Figure 3 is a horizontal sectional view on an enlarged scale taken substantially on the line 3-3 of Figure 1,

Figure 4 is a detail vertical sectional view on 25 an enlarged scale taken substantially On the line 4-4 of Figure 1, Figure 5 is a detail vertical sectional view taken substantially on the line 5-5 ofFigure 1 Figure 6 is a detail sectional view taken sub- 3 stantially on theline 6-6 of Figure 5,

Figure 7 is a vertical sectional view on an enlarged scale taken substantially on the line 'I'l of Figure 3,

Figure 8 is a horizontal sectional view taken 35 substantially on the line 88 of Figure '1,

Figure 9 is a detail vertical sectional view taken substantially on the line 9-9 of Figure 8,

. Figure 10 is a fragmentary view of the rear end of a dumping truck body illustrating the tall 40 gate as being swung to open position upon its lower pivotal points,

Figure 11 is a view similar to Figure 10 illus-' trating the body of the vehicle as elevated to dumping position with the tail gate swinging 45 about its upper pivotal points, and;

Figure 12 is a diagrammatic view partly broken away illustrating the power actuating mechanism of the tail gate.

The invention is herein illustrated as embodied 50 in a dumping truck. In the drawings the truck chassis is designated 20, the body being designated 2|. I The body is pivotally mounted on the chassis as at 22 and is adapted to be moved about its pivotal point by a suitable body ele- 55 vating means of any desired type.' The truck illustrated is of the motor ,type and carried by the steering column 23 thereof, there is a cont is trol valve 24 the functions of which will be ,hereinai'ter more specifically described.

At its rear end, the truck body is provided at each side with a plate 26 commonly known in the art as a gusset plate. Each of these gusset plates is spaced fromits respective side wall of the truck body, which construction forms.

a housing 26 in which the operating elements of the power operating meansof the tail gate may be conveniently enclosed.

The tail gate is designated by the reference character 21 and as illustratedin Figures 10 and 11, is adapted to swing to its open position aboutrequire and the construction by which this is accomplished will now be specifically described.

First, the lower pivotal. mountings of the tail gate will be described and inasmuch as these pivotal mountings are the same on each side of the truck body the description of one pivotal mounting will sufiice. Referring to Figure 8, it will be noted thatthe side wall of the truck body, which side wall is designated 28, has an ofl set or extension 29 which is connected to the gusset plate 26 by means of an end wall 38. This construction provides an extension 3| of the housing 26 between the gusset plate 25 and the side wall 28 of the truck body and this extension of the housing 26 projects beyond the rear edge 32 of the bottom 33 of the truck body as shown in said Figure 8. k

The pivot for the tail gate is mounted in this housing extension/ 3| and is best illustrated in Figure 5. Resting upon the bottom wall of the housing extension 3 I, there is a supporting bracket 34 which is of U-shaped cross sectional form and which may be secured to the bottom wall 33 of the housing extension 3| by a bolt or the like 35. The inner leg of the supporting bracket 34 is provided with an opening 36 which registers with an opening 31 in the extension 29 of the side wall 28 of the truclqbody for a purpose' -shaft 48. A counterweight 4| is secured to the stub shaft 48 by means of a cross pin 42 and one edge of this counterweight may have engagement with the inner leg of the supporting brackets through which the stub shaft' passes, thus in effect providing a thrust bearing for the stub shaft 48. The projecting end ofthe stub shaft, which is its inner end, is provided with a slot 43,-the purpose of which will be hereinafter described By this constructiom'the stub shaft is free to rotate in the collar bearing 38 and the alined openings 36 and 31 respectively in the supporting bracket and the angular extension 29 of the side wall of the truck body.

As heretofore stated, one of these stub shafts is arrangedat each side of the truck body and.

saidstub shafts 16m the lower pi'vots about which the tail gate swings.

The tail gate 21 is provided upon its lower edge with a bar or the like 4I,'the ends of which are rounded and extend slightly beyond their;

respective side edges of the tail gate and are providedwith reduced extensions 46 which are, adapted to be receivedin the slots 43 of the inner ends of their respective stub shafts 48 as best illustrated in-Flgures 5 and 9'.

By this construction itwill be obvious that the lower end of the tail gate is free to' swing extensions 46- of the .bar 46 being free to move Means is provided to retain each of the exoutwardly of the .end of the 'body, the reduced 3 tensions 46 in'the slot 43 of its respective stub shaft 48 as best illustrated in Figure 9. This means comprises a hook 41 pivotally mounted as at 48 upon the side wall of the truck body. The. hook 41. has a nose portion 49which passesover the projected. inner end 'of' the stub shaft 48 to apoint where it overlies the extension ofthe bar 45, which construction prevents movement, of the extension 46 relatively to the bar 45-so' long as the hook is maintained'in the position in which it is illustrated-in'l igurea Means is provided to retain the hook normally in that position in. whichit is shown in Figure 9, and this means consists of a coil spring 68 mounted upon the angular extension 29 of the side wall of the truck body and a depending'leg 6| of the hook 41. The spring 68 is supported upon a threaded bolt 52 which threaded bolt performs another function which will be hereinafter speextensions 46 of the bar 45 being retained in the slots 43 in their respective stub shafts 48 by the hooks 41 during a partial movement of the tail gate about its lower pivotal points and by the. blocks 48"heretofore mentioned as the slots in the stub shafts 48 pass free of the nose portions 49 of the hooks 41. 7

While I have described but oneof the pivotal mountings, it is to be understood that there are four such pivotal mountings, there being one at each lower comer of the rear end of the truck body and one at each of the upper comers of the rear end of the truck body. There is a slight difference, however, between the pivotal mountings in the lower corners of the truck body and those at the upper corners thereof since it will be obvious that the upper corner pivotal mountings' are carried by brackets which are similar to the brackets 34 except that they are inverted and further it will be obvious that the blocks 46' employed in connection with .the lower corner pivotal mountings are not necessary.

The tail gate is adapted to be operated by fluid pressure preferably compressed air and the operating.fluid is supplied from astorage tank a pipe line 8| to a suitable control or distributing valve 24. The valve 24 maybe of any conventional type having five outlet ports, one of which consists of an exhaust for all lines and will be hereinafter referred to as the neutral position. The valve in controlling the supply of fluid under pressure from the pipe line 6| to the various outlet ports thereof is' manually operated by means of a valve handle 53 and said handle has an index pointer which indicates theproper position of the valve to open the various ports with respect to the interior of the valve and it is to be understood that when the valve is in the position shown in Figure 12 with its index portion 54 at 15 the position designated E in said figure, the intenor of the valve will be open to atmosphere and the pipe line will be closed, and when the valve is moved to open any one of the ports, the pipe line 5| will be opened to the interior of the valve housing. The ports of the valve, other than the exhaust port, are designated l, 2, 3

and 4. Leading from the port designated there is a pipe line 55; leading from the port desig-' 'nated 2, there is a pipe line 56; leading from the port designated 3, there is a pipe line 51, and; leading fromthe port designated 4, there is a pipe line 58.

The pipe line 55 connects by means of a coupling 59 with a pipe line 15 having two legs 1| and 12. The leg 1| of the pipe line 10'leads to a horizontally disposed cylinder 13 while the leg 12 of said pipe line leads to a horizontally disposed cylinder 14.

The cylinder 13 is mounted upon the outer face of one side wall of the truck body, adjacent the corresponding upper pivotal point of the tail gate, while the cylinder 14 is mounted upon the opposite side of the truck body in a similar location. Movable in each of the cylinders 13 and 14 there is a piston 15 and extending from each piston 15 and projecting through one end of its respective cylinder, there is a piston rod 11. The

cylinders 13 and 14 are so arranged with relation to their respective pivotal points of the tail gate, that the piston rods 11will, when they are projected fromtheir respective cylinders, engage the depending legs of their respective hooks to move said hooks about their pivotal points and rock them out of engagement with their respective stub shafts to permit offree passage of the extensions of the tail gate from the slots therein.

This pivotal movement of the hooks is limited or determined by adjustment of the threaded bolts 52. As the hooks are rocked about their pivotal points their respective springs 50 are placed under tension in order that the hooks 41 and the pistons 15 may be returned to their normal positions under the influence of the tension in the springs 58 when pressure'is relieved from the cylinders 13 and 14.

The pipe line 51 is connected by a coupling18 to a pipe line 19 having two legs 80 and 8|. leg 80 of the pipe line 19 leads to a cylinder 82, the leg'8l of said pipe line leading to a cylinder 83. -The cylinders 82 and 83 are located on the outer faces of the side walls of the truck body near the bottom thereof, there being one cylinder at each side of said truck body. The cylinders 82 and 83 are of the same construction as the cylinders 13 and 14 heretofore described and they are arranged one upon each side of the truck body adjacent the lower pivotal points of the tail gate and so positioned with respect thereto that their piston rods 11 engage the depending legs 5| of their respective hooks 41 of the lower The.

pivotal points of the tail gate. 'These cylinders and their piston rods operate in the same manner as the cylinders 13 and 14 and their piston rods, to operate the hooks of the lower pivotal points of the tail gate which operation has been heretofore described. 1

There are two power cylinders ateach sideof the truck body for operating the tail gate. One 'of these cylinders on each side is adaptedto operate the tail gate when it is swung-about its lower pivotal point and these cylinders are designated 90 in the drawings. Each of these cylinders'90 has a piston 9| therein and extending from each of the pistons, there is a piston rod 92. Each piston rod 92 is connected to a block 99 slidably mounted in a guideway 94' and pivotally connected to each block there is a link 95 and each link 95 is pivotally connected as at 95 to its respective counterweight 4|. The cylinders 90 are of the double action type, that is to say, that pressure may be admitted to either end thereof to move the piston in either direction, as desired. When the tail gate is closed, the pistons 9| in the cylinders 90 are at-the lower ends thereof and upon admission of, fluid pressure to the lower ends of the cylinders, the pistons will be moved upwardly therein and through the medium of their piston rods and links will exert an upward pull upon their respective coun terweights 4| and rock the stub shafts in their weights 4|- are keyed to the stub shafts. By this rocking movement of the counterweights the tail gate, through the engagement of its reduced extensions in the slots of the stub shafts, will be swung about its lower pivotal points.

It is to be understood, however, that before the tail gate can be swung about its lower pivotal points, the upper hooks 41 must be disengaged with the upper extensions, of the tail gate and this is accomplished by admission of fluid to the cylinders 13 and 14 to operate the pistons in the manner heretofore described.

Fluid pressure for moving the pistons 9| upwardly of the cylinders 90 is supplied by pipe lines 95 and 91; The pipe line 95 leads directly from the pipe line 1| heretofore mentioned while the pipe line 91 leads directly from the pipe line 12 heretofore mentioned, The pipe lines 95 and 91 are connected with their respective pipe lines 1| and 12 by means of a pressure retarding valve 98. These valves 98 are of the type that, when fluid under pressure is admitted to the pipe line 1|,

operation of the upper hooks 41 to move them to the dotted line position'shown in Figure 7, and then, as the pressure'in the pipe lines 95 and 91 is built up to maximum pressure, the pistons in the cylinders will be elevated and efiect movement of the tail gate about its lower pivotal points as illustrated in Figure 7. As the tail gate reaches the horizontal position, the

counterweights 4| engage with stops I00 carried by the rear wall of the housing extensionjil which may be adjusted so that as the piston reaches the upper end of its stroke thecountera bearings, it being remembered that the counter- 4. p H weights will engage thetstops, thus supporting the tail gate in said horizontal position.

Having described the manner in which the tail gate is moved. about its lower pivotal points to the open position, I will now describe the mannor in which the tail gate is moved from its horizontal open position toits closed position.

The pipe line is connected by a coupling III to a pipe line I02 which has two legs I03 and I04. The legs I03 and' I04 lead to their respective cylinders 90 and admit fluid under pressure to the upper ends thereof on top of-the pistons II which move therein. Admission of fluid to I the upper ends of the cylinders 90 forces. the

therein.

35 Exhaustion of the pipe lines "and "releases pistons 9| therein downwardly and through the medium of the link connections 90 and with the aid of gravity, the counterweights 4I- are returned to their normal positions in which they are shown in full lines in Figure '7, which movement moves the tail gate about its lower pivotal to the closed position. v

To admit fluid under pressure to the tops or upper ends ofthe cylinders 00, 'the valve 24 is points operated by means of its handle- 03 to move its index pointer 84 to'coincidewith the port desig-.

nated E to'exhaust the pipe lines 60 and I0 after which the valve handle is moved until its index pointer coincides with the port designated 2.v

With the valve in this position fluid-pressure is admitted from the valve to the pipe lines 86 and I02 to the upper ends of the cylinders 90 and operates 'hoolgsretain the upper extensions 46 in the slots of the upper stub shafts 40 to secure the tail gat in its-closed positi y g Y After the tail gate has reached its closed pos'i- 'tion, the valve handle 63 is moved so thatits index pointer coincides with the port designated ,E to exhaust the pipe lines stand I02, leaving the system devoid of, fluid pressure beyond the valve 24. I

Inaddition to the power cylinders 90, heretofore described as operating the tail gate about its lower pivotal points, there are two power cylinders H0, they being arranged one at each side of the truck body preferably mounted upon the same brackets as carry-the power cylinders 90 heretofore mentioned. These cylinders IIO operate the tail gate when it is moved to open position about its upper pivotal points, by power.

When it is desired to open the tall gate by swinging it about its upper pivotal points with the truck body .in a. horizontal plane, the valve handle is moved until its index pointer coincides with the port designated 3 in which position fluid under pressure is supplied to the pipe lines 01 and IS. The fluid 1n the pipeline 1! passes to the cylinders 82 and 03 which operate the lower hooks 41' in the same manner as described;

for the upper hooks, rocking said hooks to release the lower extensions 46 with respect to the slots in the lower stub shafts 40.

Fluid under pressure is supplied to the upper ends of the cylinders li0 by pipe lines Ill and I I2 each of which extends from a valve I I3, there being one of said valves H3 in the leg 00 0f the aaaaa'oa to force the pistonsydownwardlythe pipe lines III pipe line 10, the other of said valves II! being located in the leg II of the pipe line 10. These valves I II are of the same general type asthe valves heretofore described and as pressure is admitted to the pipe lines 01 and I8, the lower hook operating cylinders 02 and 80 will receive said pressure and operate the lower hooks after which the pressurevbuilds up in the pipe lines III and H2 and the cylinders H0, and effects an operation of the pistons therein.

Each .of these cylinders has a piston H4 and piston rod III which is connected by means of a link IIO with one of the upper counterweights II! of which there aretwo arranged one at each side of the truck body arid each of which is' connected to its respective upper stub shaft 40.

From the foregoing it will be apparent then,

that if the handle 83 of the valve be turned until its index pointer. coincides with the port designated I, fluid pressure will be admitted through the pipe lines 81 and 19, legs 80 and 0i to the valves H3, and to the cylinders 82 and 83 which operate the lower hooks and moves them to the releasing'position in the same manner as described for the operation of the upper 'hooks. As the pressure builds up in the legs of the pipe line 19,, it passes through the pipe lines III and H2 to the upper ends of the cylinders IIO forc-. ing the pistons therein downwardly and through the link connections II8 the upper counterweights are moved downwardly rocking the tail gate about its upper pivotal points to open position. The tail gate may be maintained in this open position merely by maintaining pressure in the pipe lines 61 and I0 and legs 80 and 8| and .and H2.

, To movethe tail gate to closed position, under power fluid underpress'ure is admitted to the .lower ends of the cylinders IIO beneath the-pistons herein and this is accomplished in the following manner.

The pipeline 08 is connected by means of a I coupling I to a pipe line I2I which has two legs I22-and I23. The leg I22 of the pipe line I2I is connected to the lower end of one of the cylinders 1 I 0, the leg I 20 of the pipe line I2I being connected to the lower end of the other cylinder I I0. Thus, when the valve handle 63 is operated to move its index pointer to the position designated E to exhaust the pipe lines 61, I9, III and H2, and subsequently moved to the port designated 4, fluid under pressure will be admitted to the pipe lines 40 and HI and the legs I22 and I23 thereof and to the lower ends of the cylinders 0 to force the pistons upwardly of their cylinders.

The tail gate may also be moved to the open position about its upper pivotal points by the weight or pressure of the load in the truck body if the truck body be elevated to dumping position as illustrated in Figure 11 and this phase of the operation will now be described.

with the parts 'in the neutral position heretofore mentioned, if the handle 63 of the valve be grasped and the valve turned until the index pointer coincides with the port designated. 3, pressure will be admitted to the pipe lines 61, I0,

, legs 00 and M of the pipe line I0 through the valves II3 to the cylinders .82 and 83, releasing it will be seen that the lower hooksmay be o'perated to release the lower end of thetail gate and permit its swinging about its upper pivotal points under the influence of the load to be dumped and without any operation upon the part of the cylinders 0. I

From the foregoing, it will be apparent that the present invention provides a novel mechanism for'operating the tail gates of vehicles by means of power in such a manner that the tail gate may be operated to swing about either upper or lower pivotal points as the case may be. Furthermore, after a selection as to the pivotal points about which it is desired to swing the tail gate, the operation of releasing the holding means and subsequent operation of the tail gate are performed automatically in their proper sequence a V The invention has been herein illustrated in its preferred form but it is' to be understood that it is not to be limited to the specific constructions and form shown and that it may be embodied in such other forms as rightfully fall.

1. Tail gate operating means for dumping vehicle bodies comprising in combination, a vehicle body, a tail gate therefor, means for pivotally mounting said tail gate at its upper edge to per-,

, mit of free swinging movement of the lower edge of the tail gate, means for pivotally mounting said tail gate at its lower edge to permit of free swinging movement of its upper edge, means for holding said tail gate against swinging movement about its upper edge, means for holding said tail gate against swinging movement about its lower edge, fluid operated means for selectively operating said tail gate holdingmeans to se- 1 lectively release them and permit of swinging movement of the tail gate about either its upper or lower edge and for operating the tail gate after either of the holding means has been released, and control means forsaid fluidoperating means for preventing operation of the tail gate until after the selected holding hooks have been released.

2. Tail gate operating means for tail gates of edge, means for normally retaining the tail gate in operative engagement with both upper and lower pivotal means to retain the tail gate in its closed position, means for selectively releasing the upper or lower tail gate retaining means, and for operating the tail gate after release of either the upper or lower tail gate retaining means has been released, and means for preventing operation of the tail gate until after the selected tail gate retaining means has been released.

3. Tail gate operating means for the tail gates of vehicle bodies comprising in combination, a

vehicle body, a tail gate for closing. one end of the vehicle body, and means for mounting and operating the tail gate for swinging movement selectively about either its upper or lower edge to open the end of the vehicle body, said means including a rotatable stub shaft at each side of the body at the bottom thereof, means for simule taneously rotating said lower stub shafts, a rotatable stub shaft at each side of the body at the top thereof,'means for simultaneously rotating said upper stub shafts, means carried by the tail gate for releasable driving engagement with each of said stub shafts, means for retaining the tail gate in driving engagement with said lower stub shafts, means for simultaneously releasing said lower retaining means, means for retaining upper stub'shafts, means for simultaneously releasing said upper retaining means, andcontrol -meanswherebythe retaining means may be' se lectively operated to release either the upper or lower edge of the tail gate for swinging movement and subsequently to set into operation the the tail gate is retained vehicle body, a tail gate for closing one end of the vehicle body, and means for mounting and operating the tail gate for swinging movement selectively about either its upper or lower edge to open the end of the vehicle body, said means including a rotatable stub shaft at-each' side of the body at the bottom thereof, means for simulsaid tail gate in driving engagement with said taneously rotating said lower stub shafts, a rotatable stub shaft at each side of the body at the topthereof, means for simultaneously rotat ing said upper stub shafts, means carried by the tailgate. for releasable driving engagement with each of said stub shafts, means forretaining the tail gate in driving engagement with said lower stub shafts, means for simultaneously releasing said lower retaining means, means for retaining said tail gate .in driving engagement with said upper stub shafts, means for simultaneously releasing said upper retaining means, and control means whereby the retaining means may be selectively operated to release the tail gate from driving connection with either the upper or lower stub shafts torelease either the upper or lower edge of the tail gate-for swinging movement and subsequently to set into operation the stub shafts with" which the tail gate is retained in driving engagement.

5. Tail gate operating means for the tail gates of vehicle bodies comprising in combination, a vehicle body, a swinging tail gate for closing one end of the vehicle body, a plurality of stub shafts for pivotally mounting said tail gate for swinging movement, a, plurality of hooks for holding said tail gate in its closed position, means for operating said stub shafts to effect an opening or closing of said tail gate, means for moving the hooks to tail gate releasing position, and control means whereby the tail gate operating means is rendered operative subsequently to the operation of the tail gate holding hooks.

6. Tail gate operating means for the tail gates of vehicle bodies comprising in combination, a vehicle body, a swinging tail gate for closing one end of the vehicle body, a plurality of stub shafts for pivotally mounting said tail gate for swinging movement, a plurality of hooks for holding said tail gate in its closed position, means for operating said stub shafts to effect an opening or closing of said tail gate, means for moving the hooks to tail gate releasing position, and control means whereby the tail gate operating means is rendered operative to move the tail gate to its open position subsequently to the operation of the tail gate holding hooks and for operation of the stub shafts to move the tail gate to its closed position.

7. Tail gate operating means for the tail gates vehiclebodmaswingingtailgateforclosingone and of the vehicle body, a plurality of stub shafts for pivotally mounting the tail gate for swinging movement, a plurality of books for holding said tail gate in its closed position, fluid pressure operated means for moving said hooks to tail gate releasingrposition, fluid pressure operated means for operating the stub shafts to effect an-opening oi the tail gate, means for simultaneously. admitting fluid under pressure to the fluid pressurehook operating means and to the fluid pressure-stub shaft operating means, and control means for rendering inoperative'the stub shaft operating means until such time as an operation ofthe hook operating-means" has effected movement of the hooks to tail gate releasing position. I

8. Tail gate operating means for the tail gates 20 of vehicle bodies comprising in combination, a

, am of vehicle bodies comprising in combination. a

vehiclebodmaswiuglngtailgateiorclosingone end 'of thevehicie body, a plurality of stub shafts for pivotally mounting the tail gate for swinging movement, a plurality of hooks for holding said tail gate in its closed position, fluid pressure operated means for moving-said hooks to .tail gate releasing position, fluid pressure operated means for operating the stub shafts to effect an opening of the tail gate, means for simultaneously admitting fluid under pressure to the fluid pressure hook operating means and to the fluid pressure stub shaft operating means, control means-for rendering inoperative the stub shaft operating means until such timeas an operation of the hook operating means has effected movement of the hooks to tail gate releasing position,

DOUGLAS BOHNE. 20 

